The movement of air in and out of the lungs can be measured using a spirometer. The graph is a trace from a spirometer Which lettered arrow represents the tidal volume?

Answer:

1) A

A – Correct
Tidal volume is the volume of air displaced in the absence of extra respiratory effort. 

B – Wrong
B represents the total lung capacity.

C – Wrong
Inspiratory reserve volume

D – Wrong
Residual volume

E – Wrong
Inspiratory capacity